Sensing misalignment detection and estimation system

Abstract

A misalignment detection sensor assembly is provided, which includes a forward-looking sensor having a sensing direction along a first axis and an inertia sensor configured to sense acceleration along a second axis, the second axis having a fixed relationship with respect to the first axis. A misalignment detection system uses the misalignment detection sensor assembly and a signal processing system to calculate a misalignment angle between the first axis and the direction of forward motion of the sensor assembly. A method of detecting angular misalignment of a forward-looking sensor assembly is also disclosed, which includes measuring acceleration along an axis having a fixed relationship with respect to the sensing axis of the forward-looking sensor assembly and comparing the acceleration measurement with a predetermined threshold.

1. A misalignment detection sensor assembly for a motor vehicle comprising:
 a forward-looking sensor package having a housing and a forward-looking sensor, the forward-looking sensor having a sensing direction along a first axis X RAD ; and 
 an inertia sensor fixed to the housing, the inertia sensor configured to sense acceleration along a second axis, the second axis having a fixed, non-parallel relationship with respect to the first axis X RAD ; and 
 a signal processor in electrical communication with the inertia sensor, the signal processor configured to receive an acceleration signal from the inertia sensor and calculate a misalignment angle between the first axis X RAD  and a forward axis X CG , the forward axis X CG  being parallel to a direction of motion of the sensor assembly, 
 wherein the inertia sensor is further configured to sense acceleration along a third axis X SEN , the third axis X SEN  being orthogonal to the second axis and parallel to the first axis X RAD . 
 
     
     
       2. The misalignment detection sensor assembly of  claim 1 , wherein the signal processor is in electrical communication with the forward-looking sensor. 
     
     
       3. The misalignment detection sensor assembly of  claim 2 , wherein the assembly is further configured to produce an alert signal when the misalignment angle exceeds a predetermined threshold. 
     
     
       4. The misalignment detection sensor assembly of  claim 2 , wherein the assembly is further configured to compensate a sensitive measurement of the forward-looking sensor based upon the misalignment angle. 
     
     
       5. The misalignment detection sensor assembly of  claim 1 , wherein the forward-looking sensor is a radar sensor. 
     
     
       6. The misalignment detection sensor assembly of  claim 1 , the inertia sensor comprising an accelerometer. 
     
     
       7. A misalignment detection sensor assembly for a motor vehicle comprising:
 a radar sensor package having a housing and a radar sensor, the radar sensor having a sensing direction along a first axis; 
 an inertia sensor fixed to the housing, the inertia sensor configured to sense acceleration along a second axis, the second axis having a fixed, non-parallel relationship with respect to the first axis; and 
 a signal processor in electrical communication with the inertia sensor, the signal processor configured to receive an acceleration signal from the inertia sensor and calculate a misalignment angle between the first axis and a forward axis, the forward axis being parallel to a direction of motion of the sensor assembly, 
 wherein the inertia sensor is further configured to sense acceleration along a third axis, the third axis being orthogonal to the second axis, and 
 wherein the second axis extends in a direction about 45 degrees from the direction of the first axis. 
 
     
     
       8. A misalignment detection system comprising:
 a forward-looking sensor package having a housing and a forward-looking sensor, the forward-looking sensor having a sensing direction along a first axis X RAD ; 
 an accelerometer assembly configured to sense acceleration along a second axis, the second axis having a fixed, non-parallel relationship with respect to the first axis X RAD , the accelerometer assembly being further configured to sense acceleration along a third axis X SEN , the third axis X SEN  being orthogonal to the second axis and parallel to the first axis X RAD ; and 
 a signal processing system configured to receive an acceleration signal from the accelerometer assembly and calculate a misalignment angle between the first axis X RAD  and a forward axis X CG , the forward axis X CG  being parallel to a direction of motion of the sensor package. 
 
     
     
       9. The misalignment detection system of  claim 8 , wherein the signal processing system is further configured to produce an alert signal when the misalignment angle exceeds a predetermined threshold. 
     
     
       10. The misalignment detection system of  claim 8 , wherein the signal processing system is further configured to compensate a sensitive measurement of the forward-looking sensor based upon the misalignment angle. 
     
     
       11. The misalignment detection system of  claim 8 , wherein the signal processing system is further configured to determine whether a motor vehicle to which the sensor package is attached is traveling in a straight, forward direction. 
     
     
       12. The misalignment detection system of  claim 8 , the forward-looking sensor being a radar sensor. 
     
     
       13. A misalignment detection sensor assembly for a motor vehicle comprising:
 a forward-looking sensor package having a housing and a forward-looking sensor, the forward-looking sensor having a sensing direction along a first axis; 
 an inertia sensor fixed to the housing, the inertia sensor configured to sense acceleration along a second axis, the second axis having a fixed, non-parallel relationship with respect to the first axis; 
 wherein the inertia sensor is further configured to sense acceleration along a third axis, the third axis being orthogonal to the second axis; and 
 wherein the second axis extends in a direction about 45 degrees from the direction of the first axis. 
 
     
     
       14. The misalignment detection system of  claim 13 , the inertia sensor comprising an accelerometer configured to sense linear acceleration in at least two orthogonal directions. 
     
     
       15. A misalignment detection sensor assembly for a motor vehicle comprising:
 a forward-looking sensor package having a forward-looking sensor, the forward-looking sensor having a sensing direction along a forward-looking axis; 
 an inertia sensor configured to sense a first acceleration along a first axis extending in a direction about 45 degrees from the direction of the forward-looking axis and output a first acceleration signal based on the first acceleration, the inertia sensor being further configured to sense a second acceleration along a second axis extending in a direction about 45 degrees from the direction of the forward-looking axis and output a second acceleration signal based on the second acceleration, the second axis being orthogonal to the first axis; and 
 a signal processing system in electrical communication with the inertia sensor, the signal processing system configured to receive the first and second acceleration signals from the inertia sensor, calculate the difference between the first and second acceleration signals, and compare the difference to determine whether the forward-looking axis is about parallel to a direction of motion of the sensor assembly. 
 
     
     
       16. The misalignment detection sensor assembly of  claim 15 , wherein the inertia sensor is further configured to sense acceleration along a third axis, the third axis being orthogonal to the second axis. 
     
     
       17. The misalignment detection sensory assembly of  claim 15 , further comprising a second inertia sensor, the second inertia sensor being operable to sense acceleration along a third axis. 
     
     
       18. The misalignment detection system of  claim 15 , the inertia sensor comprising an accelerometer. 
     
     
       19. The misalignment detection sensor assembly of  claim 15 , wherein the signal processing system is in electrical communication with the inertia sensor and the assembly is further configured to produce an alert signal when the misalignment angle exceeds a predetermined threshold.